What does the Glow-worm Ultimate F41 fault code mean?
The F41 fault code on the Glow-worm Ultimate indicates a domestic hot water (DHW) overheat condition. This typically occurs when the temperature of the water exceeds safe operating limits, potentially leading to system damage or safety risks.
Common Causes
- Thermostat Failure: A malfunctioning thermostat may not accurately read the water temperature, causing the boiler to overheat.
- Blocked Heat Exchanger: A blockage in the heat exchanger can restrict water flow, leading to overheating as the water cannot circulate properly.
Can I fix it myself? (DIY)
It is recommended to call a Gas Safe Engineer for this issue, as it involves gas and electrical components that can be dangerous to handle without proper training. Attempting DIY repairs could void your warranty or lead to safety hazards.
Estimated Repair Cost (2026 UK Prices)
The estimated repair cost for addressing the F41 fault could range from £150 to £300, depending on whether the thermostat needs replacing or if the heat exchanger requires cleaning or replacement. This cost reflects the complexity of the repairs and the need for professional expertise.